Method of producing synthetic caoutchouc.



NI ED STATES. PATENT OFFICE.

' EVA GOTTSCHALK, 'OF NEWARK, NEW JERSEY; MANUELITA GOT'ISGHALK TITUS AND S. ROWLAND MONROE EXECUTORS 0F SAID EVA GOTTSCIHALIK, DECEASED.

METHOD or rnonuome SYNTHETIC cAoUTcnoUo.

No Drawing.

T 0 all whom 2'2. may concern:

Be it known that I, EVA GOTTSOHALK, a citizen of the United States of America, and a resident of Newark, county of Essex, and State of New Jersey, have invented certain new and useful Improvements in Methods of Producing Synthetic Caoutchouc, of which the followingis a specification.

My invention relates to the synthetic production of caoutchouc, and'consists in the conversion thereto of one or more hydrocarbon compounds of the terpene group,

My invention also relates to production of an improved caoutchouc superior to natural caoutchouc, in that it containsfsubstantially no resin and but a very small quantity of oxygen.

Caoutchouc has the molecular formula (C H that is to say, its formula is some multiple of 0 H, but so far .as I am aware, does not exist in the unitary form of C H Isoprene has the molecular formula of C H and I have found that upon the proper application of heat and pressure thereto, and particularly in conjunction with the employment of an acid reagent, the same can be readily polymerized into pure caoutchouc having probably the formula (0 11 As isoprene itself-is somewhatexpensive, I find it advantageous as one step in the process to produce thev isoprene from other substances which are not so expensive, and as an important feature of my invention herein I'break or crack pinene (C H into a plurality of other hydrocarbon compounds of which the largest proportion is isoprene. Mixtures of the various other hydrocarbon compounds, in which are included pentene 5 10), heptin 7 12), toluene (Q7 8), metaxylene (C H cymene (U I-I terpilene (C H and polyterpenes as for instance, C H are also by the process which I will describe, converted into caoutchouc form, so that except for a small Icy-product into rubber.

For commercial purposes I may use the ordinary turpentine of commerce and separate the pinene from the resin therein by fractional distillation. The pinene is readily dis- Having produced 1 the pinene either f ll to per cent. of the pinene is converted Patented June 6, 1916. 7

Application filed May 17, 1911 Serial No. 627,865.

the turpentine or otherwise, I now proceed to crack or break it up into a plurality of the other hydrocarbon compounds mentioned, and the pinene may be treated in severalways for this purpose. As an example of one of the ways I vaporize the pinene anddrive the vapors through a glass, porcelain, or sher- I ardized metal tube, heating'the same to a temperature ranging between 300 and 350 degrees centigrade; Thereafter these vapors are cooled quickly and the condensed liquid thus obtained is steam or otherwise distilled. The distillateis the mixture of hydrocarbons I require, the residue being principally tar.

produce the hydrocarbon compounds Ire- Another method of cracking the pinene to quire, is to place the pinene in a hermetically p sealed vessel which is provided with a needle valve attheoutlet, the discharge therefrom being connected with a condenser. The vessel is about half filled with pinene and heat is applied until-the entire contents of the vessel are evenly heated throughout, to a tem perature not exceeding 350 degrees centigrade. Then the .needle valve is slightly opened and the vapors allowed to expand therethrough, and then the vapors are caused to condense asquickly as possible in the condenser. The resulting liquid is'then steam tillate comprises the hydrocarbon compounds as in the first described method.

-' The mixture of hydrocarbon compounds 7 includes principally isoprene, together with ter1al at ,this point be not obtained from cracking pinene as above disclosed, then to the desired hydrocarbon compound or compounds, I now add an acid reagent. This acid reagent may be one or more of several organic or inorganic acids, among which may be mentioned acetic acid, formic acid,-

tannic acid, hydrochloric acid, nitric-acid,

- tions of these acids may be used, from onehalf of one per cent. u to as high as ten per cent. So far I have ound the best resultsfromefnploying one-half of one percent. of

each of acetic and hydrofluoric acid, being one per cent. of the acid reagent as a whole.

or otherwise distilled as before, and the,dis-' If these acids are chemically pure to start with, it is advantageous to' employ some water,'say,'abou't ten per cent., though the amount of water employed, or indeed the employment of any water at all, is not essential. Suitable closed vessels are conveniently provided forfthe mixture of hydrocarbon compounds and the acid reagent, the vessels.

' continued for the required period, which period is variable but has been found usually to be from six to eight hours. conditions mentioned the pressure in the vessels will rise at 300 degrees centigrade to about 350 pounds per square inch, and will remain at that pressure for a comparatively short time. Then though the mixture be maintained at a constant temperature the pressure will be seen to gradually drop, and

in the course of time will drop down to around 160 pounds and at this point will re main stationary. Their remaining stationary is an indication that this part of the process is completed, and as said, this is usually after the expiration of six to eighthours.

It will be understood that the foregoing statement with regard to temperatures and pressures issolely for the purpose of fully explaining one example of my process and is not intended in any way as a limitation, for both temperatures and pressures :vary greatly under difierentconditions. For instance,--' if about three per cent. of the acid reagent be employed instead of one per cent. the temperature employed would probably be about 1 7 5 degrees, and at 17 5 degrees of temperature the maximum pressure obtained where the' vessels areabouthalf full, is about 225pounds to the square inch, and

- this pressure drops down in the process to about 90 pounds per square inch. It will also be readily understood that if the vessels are more or less than half full the-pressures will be different from those given, and still the process may be carried on, but durin the course of many experiments I have ound the example first given to be very successful in bringing about the conversion of a very high. percentage of the original materials, into caoutchouc.- It will also be understood'thatl mayv apply pressure in other ways than that above mentloned, but I have found that by hermetically sealing a vessel half filled with the liquid and'thenheating Under the meanest it to the required degree, the proper proportion of pressure is thereby developed,

and hence this is a convenient method of applying the pressure.

' gal-the process I have just described wherein pinene is first cracked or broken up into the action of the acid, the heat, and the pressure thereon is to. convert them into caoutchouc, while on the other hand, if a. single.

hydrocarbon compound, such as isoprene, be

employed, in which the formula is a factor of.

the rubber formula, the action is undoubtedly almost entirely one of polymerization.

Where isoprene alone is employed I have found that a certain quantity thereof may be polymerized into caoutchouc by heat and the acid desirable because it increases and ac celerates the polymerizing action, and increases the yield, and furthermore where the,

'a plurality of other hydrocarbon compounds,

material being'acted upon is derived from pinene, as above stated, itacts upon the other hydrocarbon compounds to' recombine them in the required form. After'th s part the resulting mass to cool down, and then steam or otherwise distil it. The distillate,

. of which it maybe said there is a very small of the process has been completed" I allow thin layers to the oxidizing action of the air 7 under, a temperature not to exceed 135 degrees centigrade, this bein similar to the method ordinarily employe for drying and oxidizing the natural viscid juices obtained from the rubber plants. The material thus produced can hardly be distinished from pure Para rubber, except for. m

thejfact that the smoky smell. and to some extent color of the ordinary commercial caoutchouc, due tothe smoke of the fire over which it-is dried, is absent. .Thiscould be artificially supplied for the purpose of the more closely simulating the natural rubber if the same were found to be desirable.'

" Other distinctions, important commercially but not noticeable to the eye however, are that the caoutchouc thus produced contains no resin and but avery small quantity of oxygen. Ordinary commercial rubber always contains resin, and likewise always contains a higher quantity of oxygen than is desirable, usually from six percent. upward. The resin has a deleterious eflect'upon the rubber and is' undesirable,

but it is always present in thenatural rub-- ber becauseit is contained in the viseid juices of theplants. The presence of pxygen 15 uiidesirable because 1t tends to emdize the rubber and shorten its life. In produ'cing synthetic rubber by my process the amount of oxygen present does not exceed four per cent., and this alone is a valuable feature of my invention. V I

- In speaking of steam or. other distillation, it will of course be understood that any of the well-lmown methods or processes in this respect-may be used, but I have found steam distillation to be desirable as aflording a ready means of controlling the ten 1 perature of the material and preventing 1t from risingto a point at which it (the material) would be injured for my purpose.

What I claim is:

l. A process which comprises heating in a closedvessel 2, distillate,-obtainable by cracking pinene into various hydro-carbons,

and distilling said hydro-carbons;thereby creating pressure and maintaining the temperature constant, while. the pressure drops and until said pressure reaches a point where it remains substantially constant.

2. A process which comprises adding an acid reagent toa distillate,-obtainable by cracking pinene into various hydro-carbons and distilling said hydro-carbons;heating the'resultant mixture in a closed vessel,

thereby creating pressure, and maintaining.

the temperature constant while the pressure drops and until said pressure reaches a point where it remains substantially constant.

f3. A process-which comprises adding an acid reagent to a distillate,obtainable by cracking pinene into various hydro-carbons and distilling said hydro-carbonsyheating the resultant mixture in a 'closed/ vessel,

thereby creating. pressure, and maintaining the temperature constant while the pressure drops and until said pressure reaches a point where itremains substantially constant, and

distilling ofi' the volatile matter.

4. A process which comprises adding an acid reagent to a .distillate,--obtainable by cracking pinene .into various hydro-carbons by passing it in the form of vapor through a tube heated to a temperature of between T 300 degrees centigrade and 350 degrees centigrade, and then cooling quickly, distilling said hydro-carbons;heating the resultant mixture in a closed vessel, thereby creating pressure and maintaining the temperature constant while the pressure drops and until said pressure reaches a point where it re-,

mains substantially constant, distilling oif the volatile matter, and oxidizing the residue.

5. A process which comprises adding an acid reagent. to a distillate,obtainable by distilling turpentine, cracking the resulting liquid into various hydro-carbons and distilling said hydro-carbons;heating the resultant product in a closed vessel, thereby creating pressure, and maintaining the temperature constant while the pressure drops due.

and until said pressure reaches a point where it remains substantially constant. 0

6. A process which comprises adding an acid reagent to a distillate,obtainable by distilling turpentine, cracking the resulting liquid into various hydro-carbons, distilling said hydro-carbons and condensing the hydro-carbons;-heating the resultant mixture in a closed vessel, thereby creating pressure,

and maintainingthe temperature constant while the pressure drops and until said pressure reaches a point where it remains substantially constant.

7. A process which comprises addingan acid reagent to a distillate,obtainable by distilling turpentine by fractional distillation at a temperature of approximately 155 degrees centigrade, cracking the resulting liquid into various hydro-carbons.

, by passing it in the form of vapor through a tube heated to a temperature of between 300. degrees centigrade and 350 degrees centi grade, and then cooling quickly and distilling said hydro-carbons;heating the resultant mixture in aclcsed vessel, thereby creating pressure, and maintaining'the pres-- sure constant while the pressure drops and until said pressure reaches apoint where it remains substantially constant, distilling off the volatile matter, and oxidizing the resi 8. A process which consists of adding an acid reagent'to hydro-carbon compounds obtained by cracking pinene,.and then applying heat and pressure to the mixture, to produce caoutchouc.

9. A process which consists in adding an acid reagent to hydro-carbon compounds obtained by cracking pinene, and subjecting the mixture to the actionof heat in a closed vessel, to produce caoutchouc. V

10. A process which consists of adding an acid reagent to hydro-carbon compounds obtained by cracking pinene, subjecting-the mixture to the action of heat not exceeding acid reagent to a distillate-,obtainable by cracking pinene into other hydro-carbons and distilling the same;subjecting the mixture to the action of heat not exceeding 300 degrees centigrade in a closed vessel, c'ooling'the product, and then concentrating the same by steam distillation;

13. A process whichconsists of adding anacid reagent to a distillate,obtainable by heating pinene to a temperature not exceeding about 350 degrees centigrade, to break it up into a plurality of other hydro-carbon compounds, and then quickly cooling the same and distilling ;and'in then heating the mixture under pressure, to produce caoutchouc.

14. A rocess which consists in adding an acid reagent to a distillate, obtainable by heating pinene to a temperature not excee ing about 350 degrees centigrade'to break it up into a plurality of other hydro-carbon compounds and same and steam distilling said compound and in then heating the mixture in a closed vessel to ate'mperature not to exceedahout 300 degrees centigrade, to produce caoutchouc. v

15. A process which consists in adding an acid reagent to a distillate,'obtainable by heating pinene to a temperature not exceeding about 350'degrees centigradeto break it up into a plurality of other hydro-carbon and then quickly cooling the and steam distilling said co1n compounds, same, pounds ;and then heating the mixture v in a closed Vessel to a temperature ranging between 175 degrees Centigrade and 300 degrees centigrade, to produce caoutchouc.

16. A process which consists in adding an acid reagent to a distillate, obtainable by heating pinene to a temperature-not exceeding about 350 degrees centigrade to break it up into a plurality of other hydr0-. carbon compounds, in then quickly cooiing the" same and steam distilling said compounds ;and in then heating the mixture to a temperature not to exceed about 300 degrees centigrade under a pressure not to exceeed about'350 pounds per square inch, to

- produce caoutchouc.

in a closed 17 a A process which consists of adding an acid reagent to a distillate,-obtainableby heating pinene to a temperature-not-ex ceeding about 350 degrees break it up into a plurality of other hydrocarbon compounds, in then quickly cooling the same, and steam distilling said compounds and in then heating the mixture to a temperature ranging between about 175 degrees centigrade and about 300degrees centigrade, and under a pressure" produced by inclosing the mixture while being heated vesselof about twice the c pacity of the said mixture;

a plurality of hydro-carbon compounds orthe 'terpene series into.

ing heat and pressure.

then quickly cooling the cenfigrade to process which consists in converting caoutchouc by the employment of an acid reagentand apply greases a plurality of hydro-carbon compounds of the terpene series into caoutchouc, by. adding an acid reagent thereto and applying heat and pressure to the mixture while the same is contained in a; closed vessel of acapacity about double that offthe mixture contained therein. i i

22. A process which consists Qinconverting a plurality ofhydro-carboneoinpounds of the terpene series into caoutchouc, by adding an acid reagent theretoand applying heat and pressure to the mixture, the heat ranging from about 175 degreescentigrade to about 300 degrees centigrade.

p 23. A process which consists' convert ing a plurality of hydro-carboncompounds of theterpene series into caoutchouc, by

adding an acidreagent thereto and applying'heat and pressure to the mixture, the heat ranging from about 175 degrees centi- 300 degrees centrigrade, the

grade to about pressure thereof being that produced by in.-

' closing the mi ture while it is being heated .ina hermetically sealed vess l} 7' 24-. A process which consists'in converting a plurality of hydro-carbon-compounds of the terpene series into caoutchouc, by adding an acid reagent thereto-and-applyingv heat andpressure to the mixture, the heat ranging from about 175 degrees centigrade to about 300 degrees centigrade, the pressure thereof being that produced by' inclosing the mixture while itis being .heated in a hermetically sealed vessel of about twice the capacity of the mixture contained therein;

25. A process which consists in adding to a. plurality'of hydro-carbon compounds of: the terpene series,

a relatively small percentage of acetic and hydrofluoric aclds, and applying heat and pressure to the mixture, for the purpose set forth. I i v EVA. GOTTSCHALK. Witnesses:

D. Hownnn HArwoon, LYMAN S. Annnnws, Jr. 

